IGF1 and diabetes mellitus: In 20 patients who were free of diabetes before pegvisomant introduction, the mean fasting blood glucose level did not change on pegvisomant: their values were 5.4±1.4, 5.1±0.9 and 5.6±1.8 mmol/l, respectively, before pegvisomant, at IGF1 normalization, and at the last available determination (NS).